Proteoliposomes with the ability to transport Ca2+ into the vesicles and hydrolyze phosphosubstrates on their surface

Author(s)

Bolean, Mayte ^[1] ; Simao, Ana Maria S. ^[1] ; Kiffer-Moreira, Tina ^[2] ; Hoylaerts, Marc F. ^[3] ; Millan, Jose Luis ^[2] ; Itri, Rosangela ^[4] ; Ciancaglini, Pietro ^[1]

Affiliation

^[1] Univ Sao Paulo, FFCLRP USP, Dept Quim, BR-14049 Ribeirao Preto, SP - Brazil

^[2] Sanford Childrens Hlth Res Ctr, Sanford Burnham Prebys Med Discovery Inst, La Jolla, CA - USA

^[3] Univ Leuven, Dept Cardiovasc Sci, Ctr Mol & Vasc Biol, Leuven - Belgium

^[4] IF USP, Inst Fis, Dept Fis Aplicada, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Archives of Biochemistry and Biophysics; v. 584, p. 79-89, OCT 15 2015.
• Web of Science Citations: 6

Abstract

We describe the production of stable DPPC and DPPC:DPPS-proteoliposomes harboring annexin V (AnxA5) and tissue-nonspecific alkaline phosphatase (TNAP) and their use to investigate whether the presence of AnxA5 impacts the kinetic parameters for hydrolysis of TNAP substrates at physiological pH. The best catalytic efficiency was achieved in DPPS 10%-proteoliposomes (molar ratio), conditions that also increased the specificity of TNAP hydrolysis of PPi. Melting behavior of liposomes and proteoliposomes was analyzed via differential scanning calorimetry. The presence of 10% DPPS in DPPC-liposomes causes a broadening of the transition peaks, with AnxA5 and TNAP promoting a decrease in Delta H values. AnxA5 was able to mediate Ca2+-influx into the DPPC and DPPC:DPPS 10%-vesicles at physiological Ca2+ concentrations (similar to 2 mM). This process was not affected by the presence of TNAP in the proteoliposomes. However, AnxA5 significantly affects the hydrolysis of TNAP substrates. Studies with GUVs confirmed the functional reconstitution of AnxA5 in the mimetic systems. These proteoliposomes are useful as mimetics of mineralizing cell-derived matrix vesicles, known to be responsible for the initiation of endochondral ossification, as they successfully transport Ca2+ and possess the ability to hydrolyze phosphosubstrates in the lipid water interface. (C) 2015 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 14/11941-3 - Are collagen and Annexin V responsible for the control in the biomineralization process?
• Grantee: Pietro Ciancaglini
• Support Opportunities: Regular Research Grants